Data in a host is usually stored in a storage system. When needing to access a certain data object in the host, for example, a data address or a file corresponding to a certain application program, the host accesses the storage system to acquire data, in the storage system, corresponding to the object. When processing an access request of the host, the storage system allocates certain system resources for current access, where the system resources of the storage system may include, for example, a memory, a CPU and so on. A control module in the storage system adjusts system resources occupied by access to each object, so that the access to each object has different quality of service, for example, different bandwidth and different delays. The procedure of adjusting access service performance by adjusting the occupied system resources is called quality of service (Quality of Service, QoS for short) control.
In the prior art, QoS control of the storage system generally adopts a QoS control manner with a granularity level of a logic unit number (logic unit number, LUN for short). Specifically, the storage system includes a plurality of LUNs. The LUN is a virtual storage unit of the storage system. Data is stored in an address range corresponding to the LUN, and the data stored in the address can be acquired by accessing the address. The control module in the storage system can perform QoS control on the whole LUN in a unit of LUN. For example, if file A in the host is stored in LUN2, QoS of a high level can be given to the whole LUN2, so that quality of access to file A is high.
The technical disadvantage existing in the QoS control in the prior art is as follows: As mentioned in the foregoing, the storage system gives QoS of a high level to I/O access to all addresses of the whole LUN2, but the host only accesses data in a certain part of the addresses (an address corresponding to file A) in the LUN2, so performing the QoS control on all addresses of the whole LUN wastes the system resources of the storage system; moreover, the system resources are limited, and if too much resources are allocated to a certain LUN, resources allocated to other LUNs are inevitably reduced, which may affect the access quality of the data in the other LUNs. Thus, the existing QoS control manner has the problems of resource waste and lower whole quality of service.